ellipse

[ ih-lips ]

noun

, Geometry.

1. a plane curve such that the sums of the distances of each point in its periphery from two fixed points, the foci, are equal. It is a conic section formed by the intersection of a right circular cone by a plane that cuts the axis and the surface of the cone. Typical equation: ( x 2 / a 2 ) + ( y 2 / b 2 ) = 1. If a = b the ellipse is a circle.

ellipse

/ ɪˈlɪps /

noun

1. a closed conic section shaped like a flattened circle and formed by an inclined plane that does not cut the base of the cone. Standard equation x ²/ a ² + y ²/ b ² = 1, where 2 a and 2 b are the lengths of the major and minor axes. Area: π ab

ellipse

/ ĭ-lĭps′ /

1. A closed, symmetric curve shaped like an oval, which can be formed by intersecting a cone with a plane that is not parallel or perpendicular to the cone's base. The sum of the distances of any point on an ellipse from two fixed points (called the foci) remains constant no matter where the point is on the curve.

ellipse

1. In geometry , a curve traced out by a point that is required to move so that the sum of its distances from two fixed points (called foci) remains constant. If the foci are identical with each other, the ellipse is a circle; if the two foci are distinct from each other, the ellipse looks like a squashed or elongated circle.

Notes

The orbits of the planets and of many comets are ellipses.

Word History and Origins

Origin of ellipse¹

First recorded in 1745–55; from French, from Latin ellīpsis ellipsis; or by back formation from the plural ellipses

Word History and Origins

Origin of ellipse¹

C18: back formation from ellipsis

Example Sentences

NASA’s 1970s Viking Mars missions had an estimated landing ellipse of 280x100km.

From Singularity Hub 

That spread, Rothermel found, drove outward in a thin, expanding edge along an ellipse.

From MIT Technology Review

That something, according to new simulations from Nesvorny, is most likely a Neptune that slipped outward on an orbit with a just-so shape—one that falls somewhere between a perfect circle and a more severely squashed ellipse.

From Popular-Science

The eccentricity of an ellipse is a measure of how stretched out it is.

From Nautilus

Similarly, imagine you are presented with an actual ellipse, with the other object being an ellipse-shaped tilted coin.

From Nautilus

A hole, though shaped like an ellipse, in which this well-hung stud had placed it would look as if a compass traced it.

From The Daily Beast

On Dec. 18, a triumphant Johnson appeared on the Ellipse outside the White House to light the national Christmas tree.

From The Daily Beast

In an orbit made elliptical by the planetary attraction the sun necessarily occupies one of the foci of the ellipse.

From Project Gutenberg

The longer axis of the ellipse is itself in constant motion in the direction in which the earth travels.

From Project Gutenberg

The form is an ellipse with axes of 620 and 513 feet, the building covering nearly six acres of ground.

From Project Gutenberg

The disk was an impossibly long ellipse now, surrounded by a vast array of smaller bodies, fragments and contents of the ship.

From Project Gutenberg

An ellipse is a figure bounded by a continuous curve, whose nature will be shown presently.

From Project Gutenberg

Related Words

• arc
• arch
• contour
• loop
• trajectory